Vortex Suppression in Stilling Pond Overflow

Four siphons of square section with sides 24 mm (0.95 in.), 38 mm (1.5 in.), 50 mm (1.2 in.) and 62 mm (2.4 in.) were tested in a model stilling pond. The dimensionless critical submergence over the siphon decreased with increase in siphon size and for a given siphon, the improvement in critical submergence varied with the baffle position along the horizontal and vertical axis of the stilling pond. The critical submergence increases in the distance of the baffle from the siphon; results with all siphons suggest that the best location for the vortex suppression is with the baffle situated at one diameter from the siphon. The optimum submersion of the baffle to prevent vortex formation was greatest for the 24 mm siphon and decreased with increase in the siphon size. A theoretical equation suggests the functional relationship between the vorticity responsible for air entrainment and variables.